Hexapod animation using Assembly4

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OficineRobotica
Posts: 210
Joined: Thu Feb 21, 2019 8:17 am

Re: Hexapod animation using Assembly4

Postby OficineRobotica » Fri Jan 17, 2020 4:10 pm

Zolko wrote:
Fri Jan 17, 2020 12:21 pm
OficineRobotica wrote:
Wed Jan 15, 2020 10:11 am
Hexapod animation using Assembly4 workbench.
very nice. Would it be possible to show the assembly tree, may-be in multi-document view ? And collapsing all parts and links, only showing their names. I'm curious in how you built-up your model.
Thank you king Zolko :)

I was planning to rebuilt the model and then release the file because:
- components are in separate files(an experiment) and I wanted to do them in one file
-components need better modeling to prevent collision at certain angles
-some LCS's are attached to actual geometry(eg. LCS2 of "pistonExtension)

But because you asked here's the file for your's to be taken:
Attachments
pistonExtension.FCStd
(39.96 KiB) Downloaded 41 times
piston.FCStd
(678.63 KiB) Downloaded 43 times
ballJoint.FCStd
(156.04 KiB) Downloaded 42 times
Base.FCStd
(110.56 KiB) Downloaded 43 times
hexaAssembly.FCStd
(42.63 KiB) Downloaded 36 times
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OficineRobotica
Posts: 210
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Re: Hexapod animation using Assembly4

Postby OficineRobotica » Fri Jan 17, 2020 4:11 pm

mobileBase.FCStd
(180.3 KiB) Downloaded 43 times
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ppemawm
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Re: Hexapod animation using Assembly4

Postby ppemawm » Sat Jan 18, 2020 8:20 pm

OficineRobotica wrote:
Fri Jan 17, 2020 4:10 pm
...here's the file for your's to be taken
Thank you for sharing your files. There is much to be learned in the details.
Quite clever method you used to link the two independent master sketches (base and mobile) solely with the mapping of the LCS's.
Hat's off to you.
OficineRobotica wrote:
Fri Jan 17, 2020 4:10 pm
I was planning to rebuilt the model and then release the file because:
- components are in separate files(an experiment) and I wanted to do them in one file
I will be interested to see how you handle this, primarily if you will be modelling in context based on a master sketch. You may find a top-down approach when designing the assembly much easier and more satisfying. With careful planning you can minimize the number of LCS's needed in the Parts and the Model > Assembly. When you model in-context the parts are already located where they belong in the assembly.
"It is a poor workman who blames his tools..." ;)
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Zolko
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Re: Hexapod animation using Assembly4

Postby Zolko » Sat Jan 18, 2020 8:57 pm

OficineRobotica wrote:
Fri Jan 17, 2020 4:10 pm
But because you asked here's the file for your's to be taken:
very interresting, thank-you.

OficineRobotica wrote:
Wed Jan 15, 2020 5:58 pm
You are absolutely correct. The top table positioning drives the position/orientation of the 6 legs. In fact, one of my problems was setting up the expressions needed for the top table orientation. In the attachment tab there is a angle value and axis values that i still need to wrap my head around of how they interact with each other. I searched for pitch yaw roll input fields , like those in the mapping mode tab but i couldn't find it. Perhaps I am missing something.
I played around with your assembly, and there is 1 thing that, indeed, you might have missed: it's that the fields in the Variables object are more powerful than you think: they can also contain code, ExpressionEngines, and also other types of elements than numbers. I added some Placement property variables, with translations in X-Y-Z, and also rotations around X-Y-Z, and in the positioning of masterMobile I set the Placement per ExpressionEngine as a compose of all those Placement properties:

Code: Select all

Variables.Translation * Variables.X_rot * Variables.Y_rot * Variables.Z_rot
and now, you can set all 6 degrees of freedom of the top-plate by setting the variables x, y, z, x-rot, y-rot, z-rot.

Please mind, this is all standard built-in FreeCAD stuff, I didn't code any of those, I just discovered them by using FreeCAD.
Attachments
hexaAssembly.FCStd
(43.49 KiB) Downloaded 40 times
try the Assembly4 workbench for FreCAD v0.19
install with Tools > Addon Manager > Assembly4 — tutorials here and here
triplus
Posts: 9475
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Re: Hexapod animation using Assembly4

Postby triplus » Sat Jan 18, 2020 9:15 pm

OficineRobotica wrote:
Fri Jan 17, 2020 7:43 am
Please comment under the YouTube video.
Nice! Note that a link to the video was added to the Glass readme:

https://github.com/triplus/Glass/issues/2
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OficineRobotica
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Re: Hexapod animation using Assembly4

Postby OficineRobotica » Sun Jan 19, 2020 7:45 am

triplus wrote:
Sat Jan 18, 2020 9:15 pm
OficineRobotica wrote:
Fri Jan 17, 2020 7:43 am
Please comment under the YouTube video.
Nice! Note that a link to the video was added to the Glass readme:

https://github.com/triplus/Glass/issues/2
Oh ...thank you. Given that I'm not a coder it is the least i can do for the community.